Automatic positioning mechanism for billets and the like



IKE

Oct. 4, 1932. F. P. DAHLsTRoM AUTOMATIC POSITIONING MECHANISM FORBILLETS AND THE L .R N N u Fhu Q gf STQ e E R f w 4 m u 4, w A mini. Q Ad m l m m @w TMR @uw N Jh 4 Y NVHWMHMUIMH .N NW WNW m, H

Oct.' 4, 1932.

F, .V DAHLsTRoM 1,880,374

AUTOMATIC POSITIONING MECHANISM FOR BILLETS AND THE LIKE Filed Aug. 4.1930 3 Sheets-Sheet 2 'mi fig@ Oct. 4, 1932.A F. P. DAHLSTROM AUTOMATICPOSITIONING MECHALNISM FOR BILLETS AND THE LIKE s sheets-sheet 5 FiledAug. 4, 1950 ill) iid

Patented Oct. 4, 1932 rssu FRANK IP. DAHLSTROM, F WORCESTl-llR,MASSACHUSETTS, .ASSG-NOB TO coNsTnuoTIoNr COMPANY, MASSACHUSETTSAUTOMTIC POSITION'ING MECHANSM FOR BILLETS AND THE LIKE Y Applicationinea August 4, 1930.` serialY 110.473,099.

The present'invention relates to the mechanical handling and positioningof elongated pieces of stock. The principles of the inven-tion can bemade use ofvin a variety of ways, but they are 'particularly applicableto `the mechanical handling -and symmetrical positioning ofunequal-length billets vor the like, such as are presented' successivelyfor charging .into a furnace or other chamber.

For the charging of billets into :a furnace, one 'well known type ofapparatus provides a mechanical pusher which engages the rear end .ofeach billet to move the same longitudinally through an opening in thefurnace wall, until the entire length of the Abillet is within thefurnace chamber; thereupon, the thuscharged billet and those precedingit in the furnace) is pushed broadside toward the -di'scharge end of theyfurnace to make room for the next'billet to be delivered longitudinallyby the charging pusher. Ifthe strokes of the latterare of uniformamplitude, it follows that inequalities in the lengths of the billetscharged thereby will produce an unsymmetrical and unbalancedarrangement-of the billets within the furnace chamber, giving rise tounequal heating eects and also to the possibility 'of disarrangement`ofthe charged material. by the action thereon of the broadside pushingdevices. Moreover, these difficulties cannot be overcome by using Aacharging pusher Whose stroke is variable at the will of an operator,since the operator who would make such adjustments is'unable to observethe progress across the furnaceriloo'r ofthe front end of any billetbeing charged; therefore any manual adjustment of the pushers strokeswould be purely a matter of guesswork. w

This invention overcomes the above-'mentioned di'iiicultiesby theprovision of mecha- Y nism which, in the handlingof successive billetsor other pieces of varying lengths. automatically procures the advanceofeach piece through such a distance as will bring the 'longitudinalcenter of every piece vto the same point in the furnace or otherchamber; in this way, regardless of variations in the lengths ofthecharged pieces, a symmetrical arrangement fof the same, with respect tothe center line of the receiving chamber is obtained, thereby assuring,in the case of a furnaceV chamber, uniform heating efects,and also theproper operation of the broad-side pushers against the mass of chargedlpieces within the' l furnace. 'According to the inventiomeach orWORCESTER, Messacnusn'rrsn CORPORATION or operative movement of thecharging pusher, Y

always fromithe same starting point, 'serves' initially to carry eachpiece into contact with a flag Vor trigger having 'a fixed location; thedistance through which'tlie pusher moves vto effect this initial contactisa variable, bearing an inverse relation to the length of the piece;

and thereafter, Vthe amplitude of the pushers I further movement, tocomplete the charging and positioning operation on the piece,.isdetcrminedm response' to saidV flag contact, by the amplitude of saidvariable initial movement so as to'reverse the pusher when its vdistancefrom a predetermined point (onthe center line ofthe furnace) is one-halfthe length of the piece being charged. I

An adaptation of the Vforegoing principles to a furnace chargingmechanism, operating Fig. 5 is a sectional view on the line 5 5 Y ofFig. 4. p

Figs. 6 and 7 are wiring diagrams. illustrating the electrical rcircuitswat. Ydierent stages in the operation of the charging Vmechani sm.

8 is a diagrammatic view, by which the operation of the invention may bedemonstrated.

. Like reference characters refer to like parts in thedifferent'figures. i

l shows in sectional plan view a furnace l Ahaving a charging opening 2,through :sov

preceding it in the furnace) "a broadsidel movement of approximately thewidth of a billet; in this manner, the way is cleared each time for thecharging ofthe next billet, and the farthest-advanced billet in thevfurnac'eis brought into line with a. discharging pusher- 4 at the otherend of the furnace, which is operated to procure the endwise delivery ofthe successive billets through an opening 5.

The endwise charging movement of each billet, through opening 2, iseffected in the present instance by a pusher head 6, suitably mounted inoverhanging relation'upon a reciprocatory carrier 7, the head 6beingadapted to pass through opening 2 well-into the furnace when the carrierlapproaches theV left hand limit of its movement, Fig. 1. The carrier 7runs on suitable guides or rails 8,- 8, being moved in any suitable wayas by a cable or chain 9 attached thereto and passing around the;pulleys 10, 10', the last named, as

I here shown, being the driving pulley for said cable, and for thispurpose being suitably connected, as by reduction gearing 11, to theshaft of areversible electric motor 12. Other reduction gearing 13connects said motor shaft to the shaft 14 of a control device 15, thelatter being of the General construction shown in Fig. 2.

Referring to-Fig. 2, and also to Figs. 3, 4 and 5, the shaft 14providesl oppositelythreaded portions 16 and 17, the former fitted witha nut 18 which is compelled alwaysto travel longitudinally when theshaft 14 rotates by reason of being. restrained against r0- tation, asfor eXample,-by thereceptionofa .l tongue 18 thereon in an elongatedslot or guideway 19.- The travelling nut 18 carries a normally-closedswitch 20, contained in an electric circuit herein after to be describedthat controls the reversal ofl motor 1 2. i

The other oppositely threaded portion 17 of 4shaft 14 hasiitted'thereto, a nut 21, normally free to rotate in unison'with saidshaft when disposed adjacent to a collar or stop 22 thereon, as shown inFig. 2. The periphery of i, nut 21 provides equally spaced ratchet teeth23, as shown in Figs. 3 and 5, with which a pawl24, pivoted at25, isadapt-ed to cooperate,

, when the nut 21 is at the outer end of screw q portion 17 against thecollar' 22 and directlv over said pawl, asshown in Fig; 2. Under theseconditions, so long as thepawl remains out of engagement with teeth 23,the -nut21 will turn in unison with the shaft, in the absence of endwisemovement thereon;l when the pawl 24 is rocked, so as to eneagethe teeth,

the nut 21 cannot rotate in the direction of arrow 26, Fig. 3, and ifthis be the direction of rotation of the shaft, said nut will start tomove inwardly on the screw portion 17. Such inward movement willcontinue, even after the teeth 23 have left the pawl 24, because saidteeth will then be in engagement with an elongated stationary projection27 (see Fig. 5)` which holds saidY nut against rotation. If thedirectionof rotation of shaft 14 is that ofthe arrow 28, Fig. 3, whenthe 'pawl' 24 engages with teeth 23, the nut 21, when disposed againstthe collar 22, will turn with said shaft, because the teeth 23 canratchet past the pawl 24.l

Y The pawl 24, as shown inFig. 3, has a link connection 29 with theplunger of a solenoid 30 ,when the' latter is energized, said pawl isprevented from engaging the teeth'23; decnergization of said solenoid,as by breakingof the electrical circuit iny which it is contained,renders said pawl operative to hold the nut 21 against rotation, `asabove described. As shown in Fig. 1, apivoted flag or trigger 31 isdisposed adjacent the charging opening 2 in position to be struckandrocled lby the front end of each billet successively acted upon bythe charging pusher 6. v In its normal position,.in the absence ofbillet engagement, said iag or trigger 31 engages with a stationaryContact 32, thereby to close an electrical .Cire

cuit which, as hereinafter described, contains the solenoid 30, whoseenergization keeps the pawl 24 out of action. At arcertain'pointin eachcharging movement'of pusher 6, the billet being charged strikes thetrigger 31, and opens this circuit at the `contact 32, therebydeenergizing the solenoid 30and, .through pawl 2 4, inauguratingtheinward travel of nut 21-along screw portion 17 this .point comes atdifferent times, dependingupon the length of the billet being charged;with a long billet, it `comes early*l in the chargingmove ment of thepusher, and with a short billet it comes later. A A.

Referringfnowto the wiring diagram of Figs. 6 and 7 ,the motor 12,switch 20, solenoid 30 andV flag switch 31, 32 are shown in theirrespective circuits in connectionA with a control switch 33 and a doublepole reversing switch 34, the -electrical current supply having its plusand minus sides at 35, 36, respectively. The master switch carriesthree'bars 37, 38 and 39 which, in the on position of said switch shownby Fig. 7, connect respectively the pairs ofspaced stationar7 contacts40, 40, 41, 41,.and 42,42; in the olf position of saidswitch shown inFig. 6, the bar 37 connects the pair ofspaced stationary contacts 43,43. vThe reversing switch y34 comprises members 44 and 45, pivotedrespectively at 46 and 47, and connected by a link 48 for movementiii-unison. Said movement is effected by the plunger 49 of a solenoid50; when the latter is energized, the switch bars 44 and 45 nthisposition the pairs of spaced stationary` contacts 56, 56 and 57, 57,respectively; also in this position, the member 45 connects a stationarycontact 58 with the pivot 47, the

` latter having a conductor 59 running to the motor V12'. In the otherposition of reversing switch 34, the bar 51 connects a fixed contact 60with pivot 46, andthe member 45 connects a Xed contact 61 with pivot 47.

Let it be assumed that the pusher 6 is in its full retracted positionshown in Fig. 1, this corresponding to the maximum separation of thenuts 18 `and 21, as indicated on Fig. 2, the motor 12 being inoperative,and the shaft 14 at rest. By any suitable means, not shown, one of theybillets z is deposited in the path of pusher 6, in line with opening 2,for charging into the furnace. In order to initiate-a single cycle ofpusher operation, the control switch 33 is first moved into the olfpositionshown by Fig. 6; this establishes a circuit for the energizationof solenoid 50, the current flowing by conductor 35 to contact 52,throughv 'gthe solenoid 50, and thence by way` of bridged contacts 43,43 to the minus side 36 of the supply. y With the solenoid 50 thusenergized, the reversing switch 34 moves intothe position shown in Fig.6, and this establishes a holding circuit for solenoid 50, in parallelwith the bridged contacts 43, 43, the flow of current from said solenoidbeing through the bridged contacts 56, 56, and then through the closedswitch on nut 18' and the closed switch 63 back to the minus side 36 ofthe electrical supply. Inthis position of the reversing switch, themotor 12, when its circuitr is completed, will run in the direction thatproduces the charging stroke of pusher 6, being the directioncorresponding to rotation of shaft 14 in the direction of arrow 26,which causes the nuts 18 and 21 to approach each other. V

To inaugurate the operation of motor 12 and its control device 15, theswitch 33 is shifted into the on position shown in Fig. 7 by thismovement, notwithstanding the opening of contacts 43, 43, bydisengagement of the bar 37, the energized condition of sole- 2 noid 50remains undisturbed, because ofthe holding circuit established forsuchsolenoid through the Ybridged contacts 56, 56, and closed switch 20.Hence, initially,the reversing switch 34 maintains the position shown inFig. 6, notwithstanding movement of control switch 33 to the onposition. 'Referring to Fig. 6, and assuming control switch 33 in its onposition, two circuits are established; one of them energizes thesolenoid to draw the pawl 24 away from the nut 21,

the iiow ofcurrent, in this instance.being through the bridged contacts41,41, bridged contacts. 57, 57, closed flag switch contacts 31,

32, solenoid 30, and bridged contacts 40, to,

the minus side 36 of the electrical supply; The other circuit soestablished is through the. motor 12, to inaugurate the lattersoperation; theiow of current in this instance is by conductor 35 tocontact 52, thence through bar 51, pivoty contact 46, conductor 53, .7

bridged contacts 42, 42 through the motor 12 and then byy way ofconductor 59, pivot contact'47', switch member 45 and contact 58 totherminusA side 36 ofthe supply line.

As'the carrier 7 vstarts to travel inwardly from itsfull-retracted.position, Fig. 1, a proj ection 7 Y thereon moves intoclosed position a switch62 (Figs.`6 and 7): which connects the opencontact 61 withtheplus side 35 of the electrical supply.. The inwardmovement of carrier 7 isv accompanied by rot-ation of shaft 14 in thedirection: of arrow 26, and this produces inward movement of nut 18, butnot of nut 21, the latter having been released by pawl 24, so that itrotates initially in unison with shaft 14. However, when the `billet t",under the influence of inwardly moving pusher 6, contacts at its frontend with the trigger 31, the latter is moved away from contact 32,thereby vopening the circuit of the solenoid 30; thereupon, by thedeenergiza-A tion of said solenoid, the pawl 24 becomes operative to?.hold the nut 21'against rotation, whereby inward movement of'said nutalong the threaded portion 17 of 'shaft V14 is inaugurated. From thispoint on, in the charging stroke of pusher 6, both nuts-18 and 21participatein the approach toward each other; finally, at some point(the location of which depends upon how soon the nut 21 may have startedits inward movement) ,the nut 21 con-l tacts with the movable member'20of switch 2() on nut 18, thereby opening said switch, and breaking thecircuit of the solenoid 50.

Thereupon, by the deenergization ofsole v noid 50, the reversingswitch34 shifts into the position shown by Fig.v 7, procuring reversal of thedirection of current through motor 12, the flow ofcur'rent now beingfrom conductor`35 through closed switch 62 to coni' tact 61, thence byswitch member' 45, pivot contact 47 and conductor 59 to the motor, withY return to the minus side 36 of theelectrical supply through vcontacts42, 42, bar 39, conductor 53 and contacts 46 and'60. In this way, byreversal of motor 12, the inward stroke of pusher 6 is terminated andits outward or return strokeis begun,-the shaft l14 alsobeing reversed,so that the nuts 18 and'21 begin to recede from each other. Althoughthis recession permits the switch 20 vto closev (under the action,fOr'eXample, of a spring 20"), there is no ensuing reenergization ofsolenoid 50 to shift the reversing switch 34, since the holding circuitof said Vsolenoid 50 has been opened atthe contacts 56, 56 by theaforesaid reversal of switch 34. Also,notwithstanding the return ofswitch 31, 32 to closed Aposition (in consequence of billet t movingcompletely lpast the same), there is no effect on the solenoid 30,sincethe reversal` of switch 34 has brokenlthe circuit of said solenoidat the contacts 57,57, while the nut 21. is being held against rotationby .projection 27; hence towardtheend of the return 7 strikes'thesw'itch62to open the same,

thereby breaking the circuit of motor 12 and causing stoppage ofthemechanism 'at the completion of a single cycle of .operations thereof.ln order to repeat the cycle, for the charging of the next presentedVbillet '15,- the control switch 33 must firstbe moved into itsfoffposition (Fig. 6) to energize the solenoid and thereby restore thereversing switch 34 to the position shown in-rFig. 6; thereafter, thecontrolswitch 33is shifted to the on position (Fig. 7) tostart the motor12.

, The diagram of Fim'8, taken in'connection with Fig. 1, establishes thecapacity-of the above described mechanism to centralize different-lengthbillets in the furnace 1, so'that invariably each billet is brought to`rest in the furnace with its longitudinal center on the center line -ZJof said furnace. Assume L as the length of the longest billet receivablein the furnace, c vas the distance the retracted pusher 6 musttravelbefore billet L strikes the switch 3 1, 32, and a as the distance fromswitch 31, 32-to the stopping point of pusher 6 when the latter centersbillet Lin the furnace. Thus the total pusher movement,in the case ofbillet L, is c +Lla,'-0 representing the initial independent travel ofnut 18, and L-l-arepresenting the joint travel of the two nuts 18 and21. On Fig. 8, line lw-fw represents the full retracted position ofYpusher 6, and also the corresponding position of nut 18; line 2 2represents the outermost position of nut 21; line afm representsforbilletL the travel of pusher 6 through distance c to open switch 31, 32,said distance c measuring theindepenednt travel of nut 18; and lineg/-y, midway between e-.e and 'ca -m, represents the meeting point ofthe nuts 18 and 21, to open switch 20,+the travel' of each nut in thiscase being measured by the distance L-l-a.

For a shorter billet Z, the travel of pusher 6 required to effectopeningof switch l31, 32,

is-o-l- (L -Z 5 on Fig. 8, this distance is repre- Z+ a -im. i

N ow the total travel of the two nuts 18 andl sented as requiringinitial pusher movement from line .'w-fw to linen-m', and this disqtance, c-l- (ZI-Z), is a measure ofthe inde pendent movement of nut 18when the shorter billet Z is being charged. The line yl-Jy', midwaybetween e-z and :1f-', represents the meeting point of the two nuts 18and-21 Vin their joint movements, to complete the charging of theshorter billet Z.

i Now the pusher 6, after moving a distance 0+ (L ,Z) to engage theshort billet Z with switch 31, 32, wouldthereafter move the d istanceZ-la to travel to the point of its reversal for the long billet L. Butas shown in Fig. 8, the pusher goes farther always for the short billetthan for the long billet, the excess of travelbeing represented in Fig.8 by the distance m between the median lines -y-'g/ andrye-g/C In Votherwords, as shown Tin Fig. 1, the pusher travel to complete the chargingof the short billet Z, after engaging the latter with the yswitch 31,32, i is first through a distance Z-l-a (to the point of pusher reversal-for the long billet L), and then through a certain further distance,here called m. Therefore on Fig. 8, the travel of each nut 18 and 21, inthe period of their joint approach, lis measured by the distance 21,from rest position to meetingposition in always be the'sam'eg-therefore,from Fig. 8,

kin Vterms of total nut travel for the two cases comes the equationSolving this for m, I have @+aL-t2a=0+z+z+e+2m Inother words, thedistance/m, Fig. 1, is

alwaysnone-half the differencey of the lengths a distance consequentlyeach such shorter billet will come lto rest with-its longitudinal centercoincidin with the center line Z -Z of the furnace, (the same as assumedfor billet L), because that is theonly condition which establishes4 -g,as the projection of length L beyond length Z. 1 j i the cases of thetwo billets Ll and Z, must e 6 5 pieces, and means controlledbythelength of In the operation of the' above. described mechanism, if at anytime it is desiredto interrupt the action of'pusher 6 on any piece ofstock, the operatorcan simply move the control switch 33 to anintermediate position, between the oil position shown in Fig.. 6 and theon. position. shown in Fig.i7,' Vthereby breakingthe circuit of motor12; Also, before thef charging movement of anypiece of stock isVcompletecL/the pusher 6 can,.ii` desired, be reversed by the manualopening of a normallysclosedswitch 63, Figs. 6 and 7 in the circuit ofthe switch 20, -such opening breaking said circuitA and procuringdeenergization of the solenoid to throw the reversing switch 34.. Y

I` claim, r 1 l. In mechanism of the class described, a charging.member, meansfor reciprocating said member -to produce, by its travel inone direction, the endwise charging movements ofv successively-presentedpieces of different lengths, and automatic means for reversing saidcharging member in response to its ari, rival, on each chargingmovement, at a. point whose distance Jfrom a predetermined point issubstantially one-halt1 the length of the piece being charged.

2. In mechanism, of the class described,a charging member, means forreciprocating said member toproduce, by its travel in one direction, theendwise charging movements of successively-presented pieces of differentlengths, and means responsiveto the length of each piece or establishingthe amplitude of the charging movement of said member for said piece. s

3. In mechanism of the class described, a reciprocatory member whosemovements in one direction producethe endwise charging movements ofsuccessively-presented pieces of dilerent lengths, and means for varyingthe amplitude of such movements inverse ratio tothe lengths ofsaidfpieces.

Ll. In mechanism of the class described, a charging member, means forreciprocating said member to produce, byits travel in one direction, theendwise charging movements" of successively-presented variable 4,lengthpieces, and means responsive to the length of each piece forestablishing the amplitude of the 'charging movement of said member onsaid piece. n

` 5. In mechanism of the class described, a reciprocatory member `whosemovements in one direction procure the` endwise charging and positioningof Vsuccessively-presented pieces, and means controlled by the length ofeach piece for establishing the point atv which p the charging movementof said'member on said piece is terminated. A

6. In mechanism of the class described, a reciprocatory member for theendwise Acharging and .positioning of-successively-presented ositionino`of successiveli resented each piece for establishing the point atwhichthe charging movement of said'member on said piece isreversed.V 7. Inmechanism of the .class described, a reciprocatory member for thechargingr and pieces, adevice engaged byeach piece in its charg-V ingmovement, and means responsive to the distance moved by said member inengaging each piece with said device for determining they amplitude ofthe subsequent charging movement of said Vmember on .said piece.

8. In mechanism ofthe class described, la reciprocatory member for theendwise charging and Vpositioning of successively-presented pieces or"different lengths, a device adapted to be operated by each piece in itscharging movement, and means yfor proportioning the charging movement ofsaid member, Jfollowing operation of said device by a piece beingcharged, to the amplitude of the charging movement that produced suchengagement.

9. In mechanismV of the class described, a reciprocatory member for thecharging and positioning of successivelyfpresented pieces of differentlengths, and controlling means operative on each charging stroke of saidmember, toestablish the amplitude of said stroke in relation to thelength of the piece being charged.` s f 10. In mechanism of the-classdescribed, a reciprocatory member for the endwise charging andpositioning successively-presented pieces of dierent lengths,controlling means operative oneach charging stroke kof said member forvarying the length of saidstroke in relationto the length of the Vpiecebeing charged, and means for terminatingeach return stroke of saidmember always at the same point. v

v 11. In mechanism of the class described, a reciprocatory member forthe endwise charg-Y ing and positioning successively-presented pieces ofditlerent lengths, the charging strokes of said member being variable inlength, and thereturn strokes of said member terminating always at thesame point, a device adapted to be engaged by each piece in its chargingmovement, said engagement requiring greater or less movement of saidmember Jrrom said terminal point, depending upon the length of ythepiece being charged, and means responsive to the amplitude oi the.movement producing said engagement for establishing the amplitude ofAthe subsequent charging movement, lbefore reversal ofsaid member takesplace.

12. In mechanism of the class described, apusher `for the vfeeding andpositioning of successive unequal-length pieces, a pair kof membersl forcontrolling the strokepof said pusher, said members havingtheir maximumseparation at the starting point of said pusher, and approachingv eachother during said stroke for termination of the latter when izo theymeet, and means for restraining thev approach movement of one of saidmembers until the front end of the piece being fed reaches a point at aiiXed distance from said starting point, whereby the meeting pusherstroke, is determinedl by the length of said piece. p

13. In mechanism of the class described,.a

" pusher for the feeding and positioning of successive unequal-lengthpieces, a pair of controlling members having their maximum separation atthe starting point of said pusher, andadapted for approach during thefeeding stroke of said pusher to terminate said stroke when they meet,means for moving one of said members during the entire feeding stroke ofsaid pusher, and means responsive to the length of the piece being fedfor inaugurating the approach movement of the y other control member. i

14. In mechanism of the class described, a pusher for the feedingand'positioning of sucn cessiveunequal-length pieces, a pair of membersmovable toward each other during the feeding stroke of said pusher tocontrol the amplitude of said stroke, the latter terminating when saidmembers meet, and means controlled by the length of the piece( being fedfor delaying the approach movement of one of said members. l Y

' l5. In mechanism of the class described, a pusher for the feeding andpositioning of suc- ,y cessive unequal-length pieces, a pair of membersmovable toward eachother during the feeding stroke of said pusher tocontrol the `amplitude of said stroke, the latter terminating when saidmembers meet,means for sta-rting the approach movement of one of saidmembers at the commencement of pusher operation, and means for startingthe approach movement of the other member when the front end of thepiece being fed reaches a point at a `fixed distance from the startingpoint of said pusher. Y

16. In mechanism of the class described, a pusher for the feeding andpositioning of successive pieces of varying lengths, a pair of membersmovable toward each other during the'feeding stroke of said pusher tocontrol the amplitude of said stroke, the latter terminating when saidmembers meet, and means controlled by the length of a piece being fedfor determining the periods of separate and joint approach of saidmembers.

17. In mechanism of the class described, a Y

point of said 'members, and consequently the length of .variable-length.pieces,a member'at a hired distance from thestarting. ploint ofsaidfeeding member, and adapted to beengagedLby each piece in itsfeedingmovement, whereby the length of travel of the feeding member, toeffect said engagement, is inversely'related to the length of the-piecebeing fed, and means responsive to the amplitude of said travel forlimiting the further feeding movement of saidfeeding member, .whereby toterminate thev` feeding movement of each piece Whenits longitudinalcenter arrives at av predetermined point. e Y

Y 19. In mechanism of the class described, a

pusher for operation on successive variablelength pieces, measuringmeans brought into action by the initial movement of a piece by saidpusher, and means controlled by said measuring means to determine thetotal movement of said pusher in positioning said piece.

20. In mechanism of the class described, a pusher for-operation onsuccessive variablelengthpieces, a reversible motor'for reciprocatingsaid pusher, and'control devices responsive to the length of a piece forreversing said motor, to return said pusher to starting position. f

2l. In mechanism of the class described, a pusher for'operation onsuccessive variablelength pieces, a reversible motor for reciprocatingsaid pusher, a control device responsive to the length of a piece forreversing said motor, to return said pusher to starting position, andmeans responsive to said pushers return to starting position forstopping said motor. y

22. In mechanism of theclass described, a pusher for operation onsuccesive variablelength pieces, a reversible motor for reciprocatingsaid pusher, control devices responsive to the length of a piece forreversingsaid motor, to return said pusher to starting position, andrmeans operable by the reversal of said motor to return said controldevices to starting position. Y Y

28. In mechanism of the class described, a pusher for operationon'successive variablelengthpiece's, a motor for reciprocating saidpusher, a reversing switch for said motor, and a control switch whosemovement into one position sets said reversing switch to procure anoperative stroke of said pusherby said motor,and Whose movement intoanother positionestablishes thecircuit of` said motor.

24E. In appartus for the endwise charging andpositioning.ofVunequal-length pieces of stock, a charging pusher,-having the same lstarting point for each charging stroke, char- Ypusher for any given piece a total by substantially one-half the lengthof the piece being charged.

25. In apparatus for the endwise charging and positioning ofunequal-length pieces of stock, a variable-stroke charging pusher,havingthesamestartingpointfor each charging stroke, characterized inthis that means are provided for imparting to said pusher for any givenpiece a total charging stroke exceeding that for a longer piece byone-half the difference between the lengths of said' pieces, said meansincluding a control device, at a xed distance from said starting point,adapted to be operated by front-end engagen ment of each piece therewithin the first part of each charging stroke of said pusher.

26. In apparatus for the endwise charging and positioning ofunequal-length pieces of stock, a variable-stroke charging pusher,having the same starting point for each charging stroke, characterizedin this that means are provided for imparting to said charging strokeexceeding that for a longer piece by one-half the difference between thelengths of said pieces, said means including a control device, at afixed distance from said starting point,adapted to be operated byfront-end engagement of each piece therewith in the first part of eachcharging stroke of said pusher and a stroke-terminating device,responsive to the operation of said control device, for proportioningthe length of the final part of each charging stroke to said first partof each charging stroke.

27. In apparatus of the class described, a reciprocatory member for thefeeding and positioning of successive variable-length pieces, a devicesubstantially in the path of feed of said pieces and responsive.. to thearrival thereat of each pieces advancing end, and means controlled bysaid device for establishing the amplitude of the further feedingmovement imparted to said piece by said member.

FRANK P. DAHLsTRoM.

